Extra‐cerebral oxygenation influence on near‐infrared‐spectroscopy‐determined frontal lobe oxygenation in healthy volunteers: a comparison between INVOS‐4100 and NIRO‐200NX. (12th March 2014)

• Record Type: Journal Article
• Authors: Sørensen, Henrik; Rasmussen, Peter; Siebenmann, Christoph; Zaar, Morten; Hvidtfeldt, Morten; Ogoh, Shigehiko; Sato, Kohei; Kohl‐Bareis, Matthias; Secher, Niels H.; Lundby, Carsten
• Is Part Of: Clinical physiology and functional imaging. Volume 35:Number 3(2015:May)
• Page Start: 177
• Page End: 184
• Publication Date: 2014-03-12
• Subjects: Physiology, Pathological -- Periodicals; Diagnostic imaging -- Periodicals; 612
• DOI: 10.1111/cpf.12142
• Languages: English
• ISSNs: 1475-0961

Abstract

<abstract abstract-type="main" id="cpf12142-abs-0001"> <title>Summary</title> <sec id="cpf12142-sec-0001" sec-type="section"> <title>Introduction</title> <p>Frontal lobe oxygenation (S<sub>c</sub>O<sub>2</sub>) is assessed by spatially resolved near‐infrared spectroscopy (SR‐NIRS) although it seems influenced by extra‐cerebral oxygenation. We aimed to quantify the impact of extra‐cerebral oxygenation on two SR‐NIRS derived S<sub>c</sub>O<sub>2</sub>.</p> </sec> <sec id="cpf12142-sec-0002" sec-type="section"> <title>Methods</title> <p>Multiple regression analysis estimated the influence of extra‐cerebral oxygenation as exemplified by skin oxygenation (S<sub>skin</sub>O<sub>2</sub>) on S<sub>c</sub>O<sub>2</sub> in 21 healthy subjects exposed to whole‐body exercise in hypoxia (F<sub>i</sub>O<sub>2</sub> = 12%; <italic>n</italic> = 10) and normoxia (<italic>n</italic> = 12), whole‐body heating, hyperventilation (<italic>n</italic> = 21), administration of norepinephrine with and without petCO<sub>2</sub>‐correction (<italic>n</italic> = 15), phenylephrine and head‐up tilt (<italic>n</italic> = 7). S<sub>c</sub>O<sub>2</sub> was assessed simultaneously by NIRO‐200NX (S<sub>niro</sub>O<sub>2</sub>) and INVOS‐4100 (S<sub>invos</sub>O<sub>2</sub>). Arterial (S<sub>a</sub>O<sub>2</sub>) and jugular bulb oxygen saturations (S<sub>j</sub>O<sub>2</sub>) were obtained.</p> </sec> <sec id="cpf12142-sec-0003" sec-type="section"> <title>Results</title> <p>The regression analysis indicated that S<sub>invos</sub>O<sub>2</sub> reflects 46% arterial, 14% jugular, 35% skin and 4% oxygenation of tissues not interrogated. S<sub>invos</sub>O<sub>2</sub> follows a calculated estimate of cerebral capillary oxygenation (<italic>r</italic> = 0·67; <italic>P</italic><0·0001). In contrast, the NIRO‐200NX‐determined S<sub>c</sub>O<sub>2</sub> did not correlate with the estimate of cerebral oxygenation (<italic>r</italic> = 0·026; <italic>P</italic> = 0·71).</p> </sec> <sec id="cpf12142-sec-0004" sec-type="section"> <title>Conclusion</title> <p>For all interventions, 35% of the INVOS‐4100 signal reflected extra‐cerebral oxygenation while, on the other hand, NIRO‐200NX did not follow changes in a calculated estimate of cerebral capillary oxygenation. Thus, the NIRO‐200NX and INVOS‐4100 do not provide for unbiased evaluation of the cerebral signal.</p> </sec> </abstract>